Figure 1: High glucose levels and oligomeric Aβ increase nitric oxide (NO) and neuronal calcium [Ca²⁺]_i in acute cortico-hippocampal slices and cortical neuronal cultures.

(a) High glucose (25 mM) or oligomeric Aβ (250 nM) increase NO levels in acute cortico-hippocampal slices, monitored with DAF-FM imaging. Values are mean+s.e.m., n≥3; ***P<0.001 by ANOVA with Dunnett’s post hoc test (Scale bar, 50 μm). (b) Quantitative DAF-FM imaging of cortical neurons showing increased NO after exposure to high glucose (20 mM above ambient levels) or Aβ oligomers (250 nM). Memantine (10 μM) inhibited the increase in NO in response to high glucose. Combined exposure to high glucose and Aβ manifested additive effects on NO that were inhibited by treatment with L-NAME (1 mM). Mannitol (20 mM) was used as a control for possible effects of osmolarity. For this and subsequent panels, fluorescence intensity change was calculated as ΔF/F0, plotted as a fraction of 100. Values are mean+s.e.m., n≥40 neurons for each condition; **P<0.01, ***P<0.001, ****P<0.0001 by ANOVA with Dunnett’s post hoc test (Scale bar, 20 μm). (c) High glucose enhances Aβ-induced increases in [Ca²⁺]_i in cultured rat primary cortical neurons, monitored with fura-2/AM (n=∼15 cells for each condition); memantine (10 μM) or AP5 (100 μM) blocked the increase. Values are mean+s.e.m., n≥40 neurons for each condition; **P<0.01, ***P<0.001, ****P<0.0001 by ANOVA with Dunnett’s post hoc test (Scale bar, 20 μm).